A polyolefin is a polymer produced from a simple olefin monomer, or alkene with the general formula CnH2n. Polyolefins may be used in blown films. An example of a polyolefin is polyethylene, which is produced by polymerizing the olefin ethylene. One type of polyethylene is high density polyethylene, or HDPE. HDPE is defined by having a density of greater or equal to 0.941 g/cm3. HDPE is commonly used in a wide array of products and packaging including products such as milk jugs, laundry detergent bottles, plastic bags, garbage containers and toys. HDPE blown films may include HDPE barrier films having moisture barrier and/or vapor barrier properties.
Multiple challenges exist in producing HDPE barrier films. For example, obtaining a desired melt strength can be a difficulty with narrow molecular weight resins, resins that lack long chain branching, and resins with high melt indices. Various methods have been tried to improve these properties of barrier films.